Proteomic analysis of human sonic hedgehog (SHH) medulloblastoma stem-like cells

Human medulloblastoma (MB) is a malignant brain tumor that comprises four distinct\r\nmolecular subgroups including Sonic Hedgehog (SHH)-MB group. A leading cause of\r\nSHH subgroup is an aberrant activation of the SHH pathway, a developmental signaling\r\nthat regulates postnatal development of the cerebellum by promoting the mitotic\r\nexpansion of granule neural precursors (GNPs) in the external granule layer (EGL).\r\nAbnormal SHH signaling pathway drives not only SHH-MB but also its cancer stem-\r\nlike cells (SLCs), which represent a fraction of the tumor cell population that maintain\r\ncancer growth and have been associated with high grade tumors. Here, we report the\r\nfirst proteomic analysis of human SHH-MB SLCs before and after Retinoic Acid (RA)-\r\ninduced differentiation. A total of 994 nLC-MS buckets were statistically analysed\r\nreturning 68 modulated proteins between SLCs and their differentiated counterparts.\r\nHeat Shock Protein 70 (Hsp70) was one of the protein that characterized the protein\r\nprofile of SLCs. By means of Ingenuity Pathway Analysis (IPA), Genomatix analysis\r\nand extending the network obtained using the differentially expressed proteins we found\r\na correlation between Hsp70 and the NF-ĸB complex. A key driver of the SHH-MB is\r\ncMET whose downstream proliferation/survival signalling is indeed via PI3K/Akt/NF-\r\nκB. We confirmed the results of the proteomic analysis by western blot, underlining that\r\nP-p65/NF-ĸB activatory complex is highly expressed in SLCs. Taken together these\r\nresults define new protein feature of SHH-MB SLCs.